I am trying to load a jpeg file (its a drawing of survey data for archaeology) over an aerial base map. Yet when I do the jpeg is a blank white screen. It says that there are no co-ordinates, but I can't see how to overlay it and make it visible on my map in the right location - I tried 'define projection' but not sure I did this correctly - thanks! Neil
Did you georeference the image/raster?
If not, it won't show, and Define Projection does nothing if it doesn't have a coordinate system to work with